WO1999001021A1

WO1999001021A1 - Apparatus for harvesting aquatic plants

Info

Publication number: WO1999001021A1
Application number: PCT/SE1998/001284
Authority: WO
Inventors: Eric REMÖE; Marzena BELINA-GRODZKA
Original assignee: Remoee Eric
Priority date: 1997-07-02
Filing date: 1998-06-30
Publication date: 1999-01-14
Also published as: SE9702575D0; AU8251098A; SE509852C2; SE9702575L

Abstract

The invention relates to a harvesting apparatus for removing algae from water (15). The harvesting apparatus comprises a feeding-in head (13; 32) for alga with a rotatable feeder roller (23) which is provided with fingers (24) projecting out from the envelope surface of the roller.

Description

TITLE

Apparatus for harvesting aquatic plants

TECHNICAL FIELD

The present invention relates to a harvesting apparatus for removing algae from water.

BACKGROUND OF THE INVENTION

Due to overfeed of the sea and the lakes, many coastal areas are affected by environmental influencing algae growth. For example, the green-alga is found in both fresh- and saltwater over the entire world. It has been found that the algae in many case compete with original vegetation and animal species in bay and gulf areas. Important plant species disappear as well as fish species (e.g. codfish and flatfish) which has previously used the bays and gulfs as areas for breeding and growing. Because this environmental influencing problem is relatively new, the research is still in progress upon which consequences this problem may entail .

The long-term solution of this problem is of course to reduce the supply of nutritious substances, e.g. nitrogen and phosphor, to the sea and lakes. However, it has been calculated that it will take a long time before such a balance may be achieved, which will lead to a disappearance of the alga problem.

The short-term solution involves a mechanical clearing of bays and gulfs from algae. According to known clearing method, the algae are drawn up onto the seashore by means of a net, which is a very power demanding working method. The collected mass of alga soon starts to rot and then creates a considerable environmental problem. The mass of algae may also be sucked up into tank trucks and be moved from the area for deposition. A problem associated with this, is that the alga mass contains about 90 percent water, which leads to transporting of large quantities of water. Thus, the above described handling in it self leads to activities negatively influencing the local environment, e.g. seashores and shore meadows .

A better dewatering of the algae mass is needed, at the same time as dewatering must be so careful so that it does not lead to spreading crushed algae particles in the water which may give rise to new growth of algae. Further it is desirable that the removing operation may be performed in an economical way, so that as large amounts of algae as possible may be removed at a reasonable cost .

PROBLEM OF THE INVENTION

One of the objects of the present invention is therefore to provide a harvesting apparatus which enables an environmentally safe removal of algae at reasonable costs. Another object is to enable efficient dewatering of algae without risk of crushing them to be spread as particles in the water.

SOLUTION

For these objects, the harvesting apparatus is characterized in a feeding-in head for alga with a rotatable feeder roller which is provided with fingers projecting out from the envelope surface of the roller. Due to this design, it is both possible to lift up alga threads from the water and to work them loose from vegetation and from stone surfaces . The feeding-in head is preferably connected to a waterborne base unit with reservoir for collected algae. Due to this design of the removing apparatus, it may move along the shore to collect algae by means of the feeding-in head from within shallow waters and also up on the shore, without harming the shore area.

Preferably, the reservoir of the base unit is designed as a liquid permeable sack, which may be hung up in such a way that water may flow away from the algae mass. In this way the algae mass is carefully dewatered at the same time as it may be transported away without the need for additional packing.

According to one embodiment of the invention, the conveyor preferably comprises a flexible hose extending between a feeding- in head adjacent the surface of water and an intermediate storing unit at the base unit which unit is adapted for maintaining a lower fluid level than the surface of water. By this transport of algae from the feeding-in head to the base unit is facilitated.

According to a further advantageous embodiment of the invention, the feeder roller forms a loop roller for a plurality of endless belt segments which are arranged between the fingers and which run around a second loop roller, which forms a turning point for the belt segment loops. When the algae is moved from the feeder roller to the collecting trough a first dewatering of water from the alga mass takes place, which increases the effectiveness of the removing process .

Preferably, the collecting trough is insulated by means of walls from fluid that surrounds the feeding-in head. Advantageously, the feeding-in head comprises a flushing nozzle for feeding algae into the hose. In combination with the lower level of fluid in the intermediate storing unit, an efficient flow of material is achieved with a small effort of transport energy.

The feeding-in head is preferably provided with a screw conveyor for feeding algae in the direction of the flushing nozzle. This design makes it possible to use an advantageously wide feeding-in head.

The fluid level in the intermediate storing unit is preferably maintained by means of a pump, with a capacity which exceeds the affluent via one or more hoses, that feeds the algae further on towards the reservoir.

According to an alternative embodiment of the invention, the conveyor comprises two adjacent, in parallel planes operating conveyor belts together forming a nip for transporting algae. This alternative design of the invention may be used below the surface of water at optional depth.

Preferably, the feeding-in head comprises two adjacent, in parallel planes operating feeder belts together forming a nip for feeding in algae to the conveyor.

A problem free transfer of alga mass from the feeding-in head to the conveyor is achieved if the feeder belts overlap the conveyor belt which is arranged in the opposite plane. A careful dewatering of the alga mass is achieved if the conveyor belts are liquid permeable and running over concave loop rollers.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will in the following be further described with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a harvesting apparatus according to a first embodiment of the invention, Fig. 2 shows in a partly broken side view the harvesting apparatus shown in Fig. 1,

Fig. 3 shows in a broken perspective view the feeding-in head used in the apparatus according to Fig. 1 and 2 , Fig. 4 shows a harvesting apparatus according to a second embodiment of the invention,

Fig. 5 shows in a broken perspective view the feeding-in head used in the apparatus according to Fig. 4, and Fig. 6 shows the feeding-in head in Fig. 5 in a broken side view.

DESCRIPTION OF PREFERRED EMBODIMENTS

The harvesting apparatus shown in Fig. 1 and 2 comprises a base unit 10 in the form of a work platform which may be moored to the sea bottom by means of mooring ropes 11 in such a way that one can easily warp the platform along a section of a shore from which algae are going to be harvested. The base unit is connected by means of not shown mooring means to an intermediate storing unit 12 which may form a collecting trough for a number of feeding-in heads 13 which are connected by means of a hose 14 to the intermediate storing unit 12. The feeding-in head 13 will be described more detailed here below but is in general designed as a deplacing body which is arranged to float at the surface of water 15 for collecting algae in the vicinity of the surface of water. The hose 14 is arranged for transporting these algae from the feeding-in head in the direction of the arrows 16 to the intermediate storing unit 12. The hose 14 is provided with floats 17 which are arranged for maintaining a uniform slope between one end at the surface of water and the other end at the bottom of the intermediate storing unit 12. A feeder hose 18 with not shown pump means transports the algae further on to a reservoir 19 in the form of a liquid permeable sack at the deck of the work platform 10.

Fig. 2 shows how a person 20 uses the feeding-in head for collecting algae at a shore side by 'walking in shallow water while guiding the feeding-in head. In the course of this, there is a continuous feeding of algae down towards the bottom of the intermediate storing unit 12 which is located at a greater depth and its inner chamber 21 is separated by means of walls and a bottom from the surrounding water. This makes it possible to maintain a considerably lower fluid level within the chamber 21, than in the surrounding water which means that a flow of material is achieved by simple means between the feeding-in head and the chamber 21. Naturally, the feeding via the hose 18 must have such a capacity that it may handle an affluent corresponding to the number of connected hoses 14. For example, it may be suitable to control feeding via the hose 18 by means of a not shown float switch . In Fig. 2 the work platform is replaced by a work boat having its own propulsion machinery which boat also is equipped with a crane 22 for handling alga filled sacks 19.

The feeding-in head 13 is more clearly shown in Fig. 3 and comprises a rotatable feeder roller 23 with radially protruding fingers 24 that in this embodiment is designed as cog teeth. Endless belt segments 25 run between these fingers 24 extending with the feeder roller 23 acting as a loop roller further on around a second loop roller 26 in the direction of the arrow 27. The upper parts of these belts together form an inclined plane up onto which algae are lifted out of the water by means of the fingers 24. These fingers may have different shape depending upon which species of alga that is to be collected. The inclination of said plane is such that water may flow back off the belt while the algae is conveyed upwards past the loop roller 26 where they may fall down into a collecting trough 28. This accommodation is separated from the surrounding water by means of a rounded wall segment 29 as well as side wall segments 30 (see Fig. 1 and 2) which also comprise bearings for the ends of the feeder roller 23 and the loop roller 26.

The accordingly partly dewatered alga mass is moved sideways by means of a screw conveyor 30 out into a cylindrical end section of the trough 28. This end section forms on one hand attachment for the hose 14 and on the other attachment for a flushing nozzle 31 by means of which the alga mass is supplied with motive energy in the direction of the hose. Because this motive energy is combined with the inclination of the hose in the direction of the inter- mediate storing unit 21, very little flushing water is needed for transporting the alga mass a distance of about 20 to 30 meters with a hose inclination of about 3 to 10 degrees.

The feeding-in head 13 according to Fig. 1 to 3 is provided with not shown connection leads for electrical energy for driving the belt 25 and the screw conveyor 30 by means of electric motors. An additional connection lead supplies pressure water to the flushing nozzle 31.

Fig. 4 to 6 shows a harvesting apparatus according to an alternative embodiment of the invention. This harvesting apparatus is intended to be used below the surface of water at optional depth and is located on a suitable base unit 10, e.g. a vessel. A feeding-in head 32 comprises two rotatable feeding rollers 23 with respective parallel operating belt segments 25 and loop rollers 26 for forming a nip for feeding in algae. The feeding is aided by discs with finger 24, which are arranged on one of the feeder rollers .

The two belt units which form the feeding-in head 32 co-operates with a conveyor 33 which transports collected alga mass further up to the base unit 10. The conveyor 33 with the feeding-in head 32 forms a unit which is handled by means of a crane beam 22 on the vessel 10. The feeding-in head may be provided with a TV-camera for underwater operation in order to facilitating remote control from the vessel 10.

As Fig. 5 and 6 illustrate, the conveyor 33 comprises two at respective sides of a common plane operating, endless belts 34, 35. One of the two belts of the feeding-in head overlaps one of the conveyor belts 34. The two belts 34, 35 are preferably liquid permeable, e.g. manufactured from a metal mesh. The belt guide rollers 36 of the conveyor are preferably concave, in order to form a space for alga mass between them which makes it possible to convey the mass without compressing it too hard between the rollers.

The invention is not limited to the above described embodiments, but several variants are conceivable within the scope of the subsequent claims. For example, the feeding-in head 13 may be mounted directly onto a vessel which may propel itself through an area with algae. Further, the feeding-in head may be produced in optional width, e.g. comprising two reversed heads 13 operating towards a common feeder hose 14. The screw conveyor 30 may be replaced with other means for feeding algae past the belt segments and into the mouth of the hose 14. For this object, the flushing nozzle 31 may for example be arranged for flushing the algae past the belt segments and into the mouth of the hose 14.

Claims

1. A harvesting apparatus for removing algae from water (15) by means of a feeding-in head (13; 32) comprising a rotatable feeder roller (23) which is provided with fingers (24) projecting out from the envelope surface of the roller, c h a r a c t e r i z e d in that the feeder roller (23) forms a loop roller for a plurality of endless belt segments (25) which are arranged between the fingers (24) and which run around a second loop roller (26) , which forms a turning point for the belt segment loops.

2. A harvesting apparatus according to claim 1, c h a r a c t e r i z e d in that the feeding-in head (13; 32) is connected to a waterborne base unit (10) with reservoir (19) for collected algae.

3. A harvesting apparatus according to claim 2, c h a r a c t e r i z e d in that the feeding-in head (13; 32) is movable with reference to the base unit (10) , and that a conveyor (14; 33) is arranged between the feeding-in head (13; 32) and the base unit (10) .

4. A harvesting apparatus according to any one of claims 1 to 3, c h a r a c t e r i z e d in that the reservoir of the base unit (10) is designed as a liquid permeable sack (19) .

5. A harvesting apparatus according to claim 3 or 4 , c h a r a c t e r i z e d in that the conveyor comprises a flexible hose (14) extending between a feeding-in head (13) adjacent the surface of water (15) and an intermediate storing unit (21) at the base unit (10) which unit (21) is adapted for maintaining a lower fluid level than the surface of water (15) .

6. A harvesting apparatus according to any one of claims 1 to 5, c h a r a c t e r i z e d in that the feeding-in head (13) comprises a collecting trough (28) which in its position of use is located below the second loop roller (26) .

7. A harvesting apparatus according to claim 6, c h a r a c t e r i z e d in that the collecting trough (28) is isolated by means of walls (29, 31) from fluid (15) that surrounds the feeding-in head.

8. A harvesting apparatus according to any one of claims 5 to 7, c h a r a c t e r i z e d in that the feeding-in head (13) comprises a flushing nozzle (31) for feeding algae into the hose (14) .

9. A harvesting apparatus according to claim 8, c h a r a c t e r i z e d in that the feeding-in head (13) is provided with a screw conveyor (30) for feeding algae in the direction of the flushing nozzle (31) .

10. A harvesting apparatus according to any one of claims 5 to 9, c h a r a c t e r i z e d in that the fluid level in the intermediate storing unit (21) is maintained by means of a pump, that has a capacity that exceeds the affluent via one or more hoses (14) , feeds the algae further on towards the reservoir (19) .

11. A harvesting apparatus according to any one of claims 1 to 4, c h a r a c t e r i z e d in that the conveyor (33) comprises two adjacent, in parallel planes operating conveyor belts (34, 35) together forming a nip for transporting algae.

12. A harvesting apparatus according to claim 11, c h a r a c t e r i z e d in that the feeding-in head (32) comprises two adjacent, in parallel planes operating feeder belts (25) together forming a nip for feeding in algae to the conveyor (33) .

13. A harvesting apparatus according to claim 12, c h a r a c t e r i z e d in that one of the feeder belts (25) overlaps the conveyor belt (34) which is arranged in the opposite plane .

14. A harvesting apparatus according to any one of claims 11 to

13, c h a r a c t e r i z e d in that the conveyor belts (34, 35) are liquid permeable and runs over concave loop rollers (36) .